1. Field of the Invention
The present invention relates to a game chip, a game chip writer, a game chip reader, and a game chip monitoring system, which are applicable to game chips for use in casinos and devices or systems handling the game chips, for example.
2. Description of the Related Art
Game chips exchanged with a currency are used in live games such as poker and roulette played in casinos. The game chips are supplied by lending them in casinos; are used in games; and are paid out as a reward in the case where a player wins. These game chips are various in price. In the United State, for example, those which are as high as 5000 US dollars in price are used. The abovementioned game chips are different in color or shape, depending on their price (value) or types of casinos. However, the game chips can be easily counterfeited because their shape and structure are simple, and counterfeit game chips become a major problem associated with casino management.
In order to solve the abovementioned problem, in these days, there have been proposed that IC tags are applied to game chips (including those for use in casinos), thereby allowing a chip reader to identify identification information on a gaming facility (a casino), price, and a chip-number or the like. Examples of the related art of such type are disclosed in Japanese Laid-open Patent Publication Nos. 2001-293242 and 2003-144742. The above disclosures of the related art set forth that lowly-priced game chips for use in one casino are prevented from being illegally used as highly-priced game chips in the other casino and that the illegal use of the counterfeit game chips is prevented.
However, in the case where identification information is directly recorded in each of the game chips, a fraudulent player can acquire the identification information if he or she obtains a reading device, and can counterfeit game chips by keeping track of regularity or the like, of the identification numbers, from the identification information on the plurality of game chips.
Furthermore, in the case where a central server in a casino judges whether the game chip is counterfeit or genuine, based on the identification information provided by each of the chip readers, the central server is often overloaded due to concentration of operation. If a network connecting each of the chip readers and the central server fails, the center server cannot make the above judgment.
It is conceivable that the identification information is recorded after being encrypted in the game chip. However, even in this case, there arises a problem caused by concentration of operation or a problem associated with a network failure in the case where the central server decrypts the encrypted information or makes the above judgment. Even in this case, if the fraudulent player obtains an encryption key fraudulently, he or she can counterfeit the game chips. For example, in the case where the chip reader is installed in a so-called tray or a chip holder, the encryption key could be found if the tray or the chip holder itself is carried away altogether.
Therefore, a need exists for the advent of a game chip, a game chip writer, a game chip reader, and a game chip monitoring system, which are capable of preventing a fraudulent act without concentrating operation on a center-side device and moreover, executing a desired operation even in the event of a failure associated with a communication path.